Process for the preparation of acid alkyl sulphates



Patented May 18, 1948 PROCESS FOR THE PREPARATION OF ACID ALKYL SUIJPHATES Lonce Bert and Michael Procofiei'l, Paris, France, assignors to Soclete Anonyme dite: Soclete DInnovations Chlmiques dite: Sinnova on Sadie, Meaux-Beauval, France No Drawing. Application July 20, 1945, Serial No. 606,277. In France November 18, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires November 18, 1963 3 Claims. 01. 200-459) In a previous French patent application, dated September 28, 1943, entitled, Process for the obtainment oi sulphonated aliphatic acids and of their esters, applicant has described a process consisting in subjecting to the action of chlorosulphonic acid, in a neutral solvent, the aliphatic acids of condensation having 6 or more carbon atoms, or their chlorides, anhydrides, amides, nitriles, or esters.

Now, according to the present invention, the surprising discovery has been made that the reaction proceeds in a diflerent manner in regard to the final product, when it is applied to alkyl iormates H-COOR. Instead of sulphonated alkyl iormate SOsH-CO-OR, as expected, acid aikyl sulfate 3-8041! is obtained.

In a first phase, the aliwl iormate is sulphonated by SOsHCl, as in general, the esters H-COzR, in accordance with the equation:

n-co-on- -soanci=soan-coon+nc1 The sulphonated formate, which is unstable,

then splits into acid alkyl sulphate and' carbon monoxide:

som-co-oR=R.-soirl+co so that, finally, the reaction or chlorosulphonic acid with an alkyl iormate is expressed by the equation:

H-CO-'-OR.+SOaHCl=R-SO4H+C0+HC1 and constitutes a new method for producing sulphonated fatty alcohols, with exceptionally high yields.

Another feature of the process according to the invention resides in the fact that sulphonation is eiiected with heating, whereas, up to the present, it had been generally recommended to sulphonate fatty alcohols without heat.

trauma-4 gram-molecule of alkyl formate (amyl, octyi, lauryl, myristvl, etc. is dis- Number 40 2.163.133

solved in ten times its weight or carbon tetrachloride and 1.1 gram-molecule of chlorosulphonic acid is added thereto. The whole is heated with reflux until the discharge of gas ceases and the solvent is then distilled off. The residue 0! the distillation constitutes the desired crude alkyl sulp ate.

Starting with the acid alkyl sulphates thus obtained, these are converted without diflicuity into salts and in particular into soluble salts, such as the sodium salt RSO4Na. the ammonium salt RSO4NH4, sold in the market under the general designation of sulphonated fatty alcohols.

What we claim as our invention and desire to secure by Letters Patent is:

1. A process for the preparation of acid alkyl sulphates consisting in subjecting an alkyl iormate having the formula H-COOR wherein R is an alkyl group, to the action of chlorosulphonic acid in a neutral solvent.

2. A process according to claim 1, in which the sulphonation is effected with heating,

3. A process according to claim 1, consisting in dissolving 1 part of said alkyl iormate in 10 partsof carbon tetrachloride, adding 1.1 parts or chlorosulphonic acid, heating with reflux until the gaseous discharge ceases, distilling oi! the solvent and collecting the residue of distillation.

mioNcE Bear. mcnm. PROCOFIEFF.

REFERENCES CITED The following references are of record in the file of this patent: 1

, puma: s'ra'rns rs'rnu'rs Name Date Schrauth June 20, 1039 

